出渗对大颗粒泥沙周边水流结构及受力影响试验研究  

Experimental Study on the Influence of Injection on the Surrounding Flow Structure and Forces of the Coarse Grain

作　　者：蒋昌波[1,2] 刘易庄 邓斌[1,2] JIANG Changbo;LIU Yizhuang;DENG Bin(School of Hydraulic Engineering,Changsha University of Science ＆ Technology,Changsha 410004,China;Key Laboratory of Water-Sediment Sciences and Water Disaster prevention of Hunan Province,Changsha 410004,China)

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410004 [2]水沙科学与水灾害防治湖南省重点实验室,湖南长沙410004

出　　处：《应用基础与工程科学学报》2018年第3期515-525,共11页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51239001,51179015);湖南省研究生科研创新项目(CX2016B391)

摘　　要：为探讨出渗对大颗粒泥沙周边水流结构的影响,采用二维粒子图像测试技术对颗粒周围流场进行测量.通过分析不同出渗强度下颗粒周围立面流场结构,探究出渗作用下颗粒周围水动力结构.试验结果表明：出渗能够抑制颗粒尾部回流区的形成,减小回流区内负向流速大小;同时,尾涡尺寸随出渗强度的增大而减小,当出渗强度增加到一定值（v_s/U=0.65%）时颗粒尾部已不能形成尾涡.颗粒迎流面水流分离点即是产生＂涡量源＂的位置.出渗不断透过床面向上补水减小了流速变化梯度,从而导致负向涡量随出渗的增大而减小.对大颗粒的受力分析发现,颗粒平均起动流速随着出渗流速的增大而减小.The characteristics of the flow field around the coarse grain were experimentally investigated by applying the two-dimensional Particle Image Velocimetry（ PIV） system,so as to explore the influence of injection on the surrounding flow structure of the coarse grain. The hydrodynamic structure around grain was detected by analyzing the vertical flow field under different injection conditions. The results indicated that injection could inhibit the formation of recirculation flow at the wake area of the grain and reduce the magnitude of the negative flow in the recirculation area as well. The wake vortex size is decreased with the increase of injection intensity and the wake vortex would disappear if injection rate reached vs/U = 0. 65%. The flow separation point on the upstream surface of the coarse grain was the location of ＂vorticity source＂. The injection decreased the velocity gradient by supplying water through the bed.Consequently,the negative vorticity was decreased with the increase of injection intensity.According to the force analysis of the coarse grain,the mean incipient velocity of the grain decreased as the injection intensity increased.

关 键 词：出渗 大颗粒 PIV 水流结构 起动流速 

分 类 号：TV139.1[水利工程—水力学及河流动力学]